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(No Model.) 2 Sheets-Sheet 1.

I H. J. JOHNSON.

. STEAM ENGINE.

No. 304,269. PatentedgAug. 26, 1884.

INVE'NTOB.

N. PETERS, Phmum n neriwnmi n nnnnnn c.

(No Model.) 2 Sh'eetsSheet 2.

. H. J. JOHNSON.

STEAM ENGINEL No. 304,269. Patented Aug. 26, 1884.

FIQIK.

INVENTFCJR WITNESSES.

N. PEIERS PhMo-Ulhugupmr, Washimun. n.c.

UNrrEn STATES PATENT @rricE.

HENRY JAMES JOHNSON, OF PROVIDENCE, RHODE ISLAND, ASSIGNOR TO HENRY W.GARDNER, OF sAME rLAcE.

STEAM-ENGINE.

SPECIFICATION forming part of Letters Patent No. 304,269, dated August26, 1884.

Application filed February 29, 1884. (N model.)

2'0 all whom it may concern..-

Beitknown that I, HENRY J MEs J oHNsoN, of the city and county ofProvidence, and State of Rhode Island, have made an invention of 5certain new and useful Improvements in Steam- Engines and I do herebydeclare that the following, in connection with the accompanyingdrawings, is a full, clear, and exact description and specification ofthe same.

This invention has reference to reversible winding-engines, engines forcapstans, and other purposes which are frequently supplied with steamfrom boilers working at a higher pressure of steam than is required torun the engines at their proper capacity; and the object of theinvention is to prevent such engines from being subjected to a greaterpressure of steam than they are designed to withstand, and from beingthereby unduly strained.

To this end my invention consists of a certain combination andarrangement of the steam-cylinder with valves, whereby any excessivepressure of steam in the steam-cylinders is prevented.

In order that my invention may be fully understood, I have representedin the accompanying drawings and will proceed to describe the best modesin which I have embodied the invention for practical use.

Figure 1 of said drawings represents a side view of certain parts of awinding-engine with a relief-valve in section. represent similar views,showing variations in the application of the invention.

The winding-engine represented in Fig. 1

has two steam-cylinders, A A, connected with one engine-shaft, B, withthe cranks O O at right angles with each other. The steamvalves of thisengine are of the usual construction, and are contained in thesteam-chests D D. These steam-chests are supplied with steam through areversing-valve,.E, by which the steam and exhaust are reversed, as iswell understood by engineers, for the purpose of re- 5 versing therevolution of the engine-shaft B whenever this operation becomesexpedient. The reversing-valve also operates as a throttle or stop valveto shut-off or admit steam to the engine.

Figs. 2, 8, and 4,

In order that the steam-cylinder may not the steam-cylinder A, thereversing-valve in this case being applied to the pipe G, which suppliessteam from the reversing-valve E to the valve-chest on thesteam-cylinder. The spring which holds this valve closed is made of theproper strength to yield whenever the pressure in the pipe or passage Gbetween the reversing-valve and either steam-cylinder A exceeds apredetermined amountsay, for example, twenty-five pounds to the squareinch. Consequently, if the boiler pressure should exceed that amount andthe reversing-valve E should be opened so far as to admit to thecylinders more steam than the engines should receive, the relief-valve Fopens, and, by permitting the escape of steam, reduces the pressure ofthe steam entering the steam-cylinder to that which it is desired shouldnot be exceeded. A

In an engine having a reversing-valve such as I have described theconnecting-pipes G G become alternately steam-pipes and exhaustpipes asthe engine is run in one direction or the other; hence eachconnecting-pipe G 1s fitted with a relief-valve, F, between thereversing-valve E and the steam-valve in the steam-chest D of thesteam-cylinder, and the risk of straining the engine by an excessivepressure of steam is prevented, whatever be the direction in which theengine is caused to run by the position of the reversing-valve E.

In the engine represented at Fig. 2 the escape-nozzle of eachrelief-valve F upon one 1 connecting-pipe G is connected with the op-'posite connecting-pipe, so that whatever surplus of steam escapesthrough either reliefvalve passes into the connecting-pipe through whichtheexhaust is taking place.

In the modification represented in Figs. 3 and 4 both relief-valves arearranged in one chest, which is arranged between the connecting-pipes GG, that connect the reversing-valve E with the steam-chests D D of thesteam-cylinders; and in the modification represented at Figs. 5 and 6separate connections a are made between the steam-chest D of thesteam-valves and the chest of the relief-valves; but as the samesteam-chest is, in practical use, connected with a reversing or stopvalve (which is not shown in the drawings) these relief -valves operateupon the steam between the reversing or stop valve and thesteam-cylinder, and relieve the engine from an excessive pressure ofsteam.

With the various modifications above described the quantity of steamwhich is admitted to the connecting-pipes between the reversing or stopvalve and the steam-cylinders and the pressure of that steam isgenerally controlled by opening the reversing or stop valve to a greateror less extent, which is done accord ing to the judgment of theengineer; and, consequently, when the engine is running at its regularwork, and the engineer exercises good judgment, the relief-valves do notopen; but, if the engine be overloaded so that its motion is prevented,even a slight opening of the reversing or stop valve will admit steamfrom the boiler at practically full pressure, and in such case therelief-valve operates at once to per- -mit the escape of steam betweenthe revers- V in g or stop valve and the steam-cylinder, thus reducingthe pressure of the steam passing to the steam-cylinder, and relievingthe engine of the risk of being overstrained.

I claim as my invention- 1. The combination, substantially as before setforth, of the steam-cylinder, its steam-valve, and its reversing-valvewith a relief-valve arranged to permit the escape of steam between thesteam-valve of said cylinder and the reversing-v-alve.

2. The combination, substantially as before set forth, of thesteam-cylinder and its reversing-valve with a relief valve arrangedbetween the supply-pipes extended from thereversing-valve to thesteam-cylinder, whereby the steam which escapes through the reliefvalvefrom one supply-pipe is permitted to exhaust through the other- Inwitness whereof I have hereto set my hand this 23d day of February, A.D. 1884.

HENRY JAMES JOHNSON.

\Vitnesses:

GARDNER C. ANTHONY, WALTER F. BROWN.

